966 research outputs found
Trichloroethylene catalytic conversion over acidic solid catalysts
No full textThe conversion of trichloroethylene (TCE) vapor (1000 cm3/m3) in humid and dry conditions has been comparatively tested over several
acidic catalists: HY zeolite, silica–alumina, tungsta–alumina, and pure -alumina. Among them, alumina shows the higher activity in TCE decomposition
to COx and HCl at lower temperature (total conversion around 820 K) and no deactivation phenomena occur at the laboratory scale
time. AddingWO3 could even enhance catalytic activity. The use of alumina catalysts, although much less active than noble-metal containing
catalysts, allows, in principle, the destruction of different chlorided organics and the recovery of HCl in a versatile authotermic process
Elderly labor supply, endogenous grandparental childcare, and fertility in an OLG model
No full textThis paper explores how grandparental childcare influences fertility decisions, elderly labor supply, and economic development. We model the time elderly individuals allocate between work and caring for grandchildren. In high-income countries, higher wages lead to increased investments in children’s education and human capital. Interestingly, the decision to work in old age does not depend on economic development but on wage dynamics. Specifically, when the effective wage grows rapidly, grandparents are more likely
to work, even while caring for grandchildren. These findings highlight the importance of intergenerational time transfers in shaping economic outcomes. Future research could explore the long-term effects of aging populations on labor markets and family dynamics
Educational support by grandparents and human capital growth: an OLG model with endogenous time allocation
No full textThis study explores the role of grandparents in the education of their grandchildren within an overlapping generations model. We introduce an endogenously determined time allocation, where grandparents decide how much time to dedicate to their grandchildren's education based on a trade-off between leisure and educational contributions. The model shows that grandparental involvement in education
influences the intergenerational transmission of human capital, with the potential for long-term effects on economic outcomes. By combining theoretical analysis and simulations, we highlight the dynamic relationship between grandparental education, human capital development, and the generational transmission process
The k-logistic growth model. Qualitative and quantitative dynamics
No full textThe κ-exponential function, representing a generalization of the exponential function, has been
firstly introduced in physics, and, then, it has been considered in a noteworthy number of
fields because of its ability to take rare events into account. Among the possible applications
of this function, one of particular interest is in economics in which rare events may consist
in natural disasters, such as earthquakes that reduce the supply of capital, or epidemics or
other external shocks influencing the supply of intermediate inputs, human or physical capital.
Starting from the κ-exponential function, the κ-logistic function, which is a generalization of
the sigmoidal function, can be obtained and used to describe production functions in a unique
setting to take into account (1) several shapes usually considered in economics (i.e. concave and
non-concave production functions), (2) economies at different development levels, and, (3) the
possible occurrence of rare events. In this paper, we investigate the economic growth model as
proposed by Böhm and Kaas (2000), wherein the production function utilizes the κ-logistic
function. We provide theoretical results confirmed by extensive computational experiments
and in line with economic literature showing that a poverty trap may emerge together with
fluctuations, multistability and complex dynamics
Il Carcer nella produzione di Cardano
No full textAlongside a larger analysis of Cardano's moral philosophy since the De consolatione (1542), the essay focuses on the dialogue Carcer, and suggests a relationship between the difficulties encountered by the author in the Duchy of Milan in 1560-61, and the trial of 1570 in Bologna. Special attention is devoted to the philosophical reasons that support in the Carcer the Plutarchean sera numinis vindicta, one of Cardano's favorites topics
Comparing three possible hypoelliptic Laplacians on the 5-dimensional Cartan group via div-curl type estimates
No full textOn general Carnot groups, the definition of a possible hypoelliptic Hodge-Laplacian on forms using
the Rumin complex has been considered in (M. Rumin, “Differential geometry on C-C spaces and application
to the Novikov-Shubin numbers of nilpotent Lie groups,” C. R. Acad. Sci., Paris Sér. I Math., vol. 329, no. 11, pp.
985–990, 1999, M. Rumin, “Sub-Riemannian limit of the differential form spectrum of contactmanifolds,” Geom.
Funct. Anal., vol. 10, no. 2, pp. 407–452, 2000), where the author introduced a 0-order pseudodifferential operator
on forms. However, for questions regarding regularity for example, where one needs sharp estimates, this
0-order operator is not suitable. Up to now, there have only been very few attempts to define hypoelliptic Hodge-
Laplacians on forms that would allow for such sharp estimates. Indeed, this question is rather difficult to address
in full generality, the main issue being that the Rumin exterior differential dc is not homogeneous on arbitrary
Carnot groups. In this note, we consider the specific example of the free Carnot group of step 3 with 2 generators,
and we introduce three possible definitions of hypoelliptic Hodge-Laplacians.We compare how these three possible
Laplacians can be used to obtain sharp div-curl type inequalities akin to those considered by Bourgain &
Brezis and Lanzani & Stein for the de Rham complex, or their subelliptic counterparts obtained by Baldi, Franchi
& Pansu for the Rumin complex on Heisenberg groups
Possession
No full textThis chapter of the Historical Latin Syntax traces the evolution and use of predicative possessive constructions from Archaic to Late Latin. We demonstrate that, far from being merely a so-called “be-language”, Latin is a language where the major possessive type is based on a transitive verb (habeo) since the archaic stage. A textual, contrastive analysis of the habeo x and mihi est x types proves that between these two constructions there is a functional differentiation (i.e. syntactic and pragmatic, while the semantic level is relevant only to a minor extent). This, thus, explains: their different occurrence in the Latin corpus; their division-of-labour and, therefore, their coexistence through the history of Latin; and, finally, the diahronic evolution towards the transitive type. A comparison between the mihi est x and the genitive predicative type, which are fully differentiated on a functional plane, completes the picture of the whole architecture of predicative possession in Latin. Consequences can be drawn on the general plane, as “mixted” types (i.e. languages that are both have- and be-), such as Latin, must be taken into consideration when we approach the typology of predicative possession.
An analysis of attributive constructions is then offered, at the light of parameters such as: the order of the elements in the sequence, the definite status of the possessor/possessum constituents of the phrase, the semantic profile of the relation expressed, and the different morphological markers, etc.. Conclusions partly confirm previous hypotheses about the relation between the Latin stage and the Indoeuropean stage, while several generalizations from the typological point of view have to be adjusted (e.g. external possessor constructions).
The part on predicative possession is mainly due to Andrea Nuti; the part on attributive possession mainly to Philip Baldi. However, as the whole chapter is the result of a deep, mutual work carried on in full cooperation, the authors have agreed not to state explicitly and neatly an author-to-pages correspondence
Decomposition of hexamethylcyclotrisiloxane over solid oxides
No full textThe decomposition of hexamethylcyclotrisiloxane (HMCTS) has been studied at room temperature and in
the range 473–673 K over the surface of basic (CaO, MgO) and acidic oxides (Al2O3, SiO2). Alumina allows
the complete removal of HMCTS from synthetic biogases at 673 K. A reactive adsorption occurs with surface
silication and release of methane. The adsorption capacity of our alumina adsorbent (180 m2 g1),
until saturation, at 673 K, is 0.31 g (HMCTS) g(Al2O3)
1, which corresponds to one silicon atom per 9 Å2, i.e.
the silication monolayer capacity.
On the contrary, silica, which is an excellent adsorbent for siloxanes at room temperature, looses its
adsorption ability at high temperature as it is typical of a molecular adsorption behavior. Basic oxides
such as MgO and CaO have strong reactivity in decomposing siloxanes in the absence of CO2, but loose
reactivity when in contact with carbon dioxide because of surface carbonation
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